The LCD (Liquid Crystal Display) possesses many advantages of being ultra thin, power saved and radiation free. It has been widely utilized in, such as LCD TVs, mobile phones, Personal Digital Assistant (PDA), digital cameras, laptop screens or notebook screens, and dominates the flat panel display field.
Most of the liquid crystal displays on the present market are backlight type liquid crystal displays, which comprise a liquid crystal display panel and a backlight module. The working principle of the liquid crystal display panel is that the Liquid Crystal is injected between the Thin Film Transistor Array Substrate (TFT array substrate) and the Color Filter (CF). The light of backlight module is refracted to generate images by applying driving voltages to the two substrates for controlling the rotations of the liquid crystal molecules.
The liquid crystal display panel comprises a plurality of Red (R), Green (G) and Blue (B) sub pixels arranged in array. Each sub pixel is electrically coupled to one thin film transistor (TFT), and a gate (Gate) of the TFT is coupled to a horizontal scan line, and a drain is coupled to a vertical data line, and a source is coupled to a corresponding sub pixel. The enough voltage is applied to the level scan line, and all the TFTs electrically coupled to the scan line are activated. Thus, the signal voltage on the data line can be written into the sub pixel to control the transmittances of the liquid crystals to realize the display effect.
The liquid crystal molecules have a certain property, which is that the liquid crystal molecules will be polarized if the voltage of the same direction is applied to the liquid crystal molecules with a long period of time. Even the voltage disappears, the property of the liquid crystal molecules will be destroyed and can no longer be rotated due to the variation of the electrical field. Therefore, the liquid crystal display panel must be driven alternately. As showing images, the liquid crystal molecules are rotated with a certain frequency to prevent that the liquid crystal molecules fixedly lean to the same direction and lose the activity. At present, the liquid crystal display panel supports kinds of inversion modes, such as dot inversion mode, row inversion mode and column inversion mode. The achievement of the inversion is mainly to alternately change the positive and negative polarities of the TFT source voltage (i.e. the positive and negative polarities of the signal voltage transmitted by the data line) to realize the objective of the alternating current driving.
Please refer to FIG. 1. In the traditional pixel driving structure utilizing the column inversion mode, the nth data lines D(n) (n is a positive integer larger than 1) are alternately connected with the TFTs T of the n−1th column of the sub pixels P and the nth column of the sub pixels P at its two sides: the TFT T in the sub pixel P of the mth row (m is a positive integer), the nth column is connected with the nth data line D(n) at the right of the nth data line D(n), and the TFT T in the sub pixel P of the m+1th row, the n+1th column is connected with the nth data line D(n) at the left of the nth data line D(n); the polarities of the signal voltages transmitted by the two adjacent data lines are opposite; such arrangement can achieve the display effect of dot inversion. However, one of the two adjacent TFTs T in the same column of sub pixels P is at left corresponding to the sub pixel P, and the other is at right corresponding to the sub pixel P, and the TFT regions generally requires the Black Matrix (BM) for light shielding. The alignments of the aperture regions except the TFTs are not neatly aligned, and the arrangements of the aperture regions of the two adjacent rows of sub pixels are different. The bright and dark lines and the irregular spots (Mura) may easily appear to reduce the display quality.
Please refer to FIG. 2 showing a pixel driving structure, commonly used at present in column inversion mode, which is improved over FIG. 1. All the data lines use the wiring detouring design to make the TFTs neatly aligned in one column, and the aperture region of the corresponding sub pixels are neatly aligned, too, which can overcome the display quality issue caused by the arrangement of the aperture regions which is not neat. Nevertheless, such design increases the entire length of the data lines (about 2.5 times the length of the original data lines), which tremendously increase the resistance loading of the data lines and meanwhile, the area of the data lines overlapping with other metal lines increases, therefore, the capacitance loading will increase, too. The wrong charging rate of the panel is high. Particularly, it is more sensitive for the high resolution panel, and the panel power consumption also will increase.